ZnO thin film nanostructures for hydrogen gas sensing applications

A ZnO thin film-based gas sensor was fabricated using a SiO2/Si substrate with a platinum comb-like integrated electrode and heating element. The structural characteristics, morphology, and surface roughness of the as-grown ZnO nanostructure were investigated. The film revealed the presence of a c-axis oriented (002) phase with a grain size of 20.8 nm. The sensor response was tested for hydrogen concentrations of 50, 70, 100, 200, 400, and 500 ppm at the optimum operating temperature of 350 °C. The sensitivities towards 50 and 200 ppm of hydrogen gas at 350 °C were approximately 78% and 98%, respectively. A linear response was observed for hydrogen concentrations within the range of 50 ppm–200 ppm. These results demonstrated the potential application of the ZnO nanostructure for the fabrication of cost-effective and high-performance gas sensors.